The present invention relates to an air-bag, and more particularly relates to an air-bag to be mounted on a motor vehicle, the air-bag including a vent.
It is known that it is desirable to provide an air-bag with a vent. The vent may perform one or more various functions. The vent may be a permanently open vent, provided to ensure that an air-bag will deflate slightly when impacted, for example, by an occupant of a vehicle when the vehicle is involved in an accident. This helps prevent the occupant of the vehicle from simply bouncing back away from the air-bag and provides the air-bag with a desirable energy-absorbing characteristic.
Controllable vents may be provided on an air-bag, the vents being opened in response to specific signals or specific situations. A controllable vent may, consequently, open when a pressure in excess of a predetermined threshold is experienced within an air-bag. A vent may also be opened in response to a specific situation such as a seat being occupied by a very heavy occupant, or the occupant of a seat leaning forwardly so as to be located close to the air-bag.
The present invention seeks to provide an improved air-bag which incorporates a vent.
According to the present invention there is provided an air-bag, the air-bag incorporating regions of fabric which define a mouth, the mouth being mounted to an air-bag housing, at least part of the mouth being mounted to the housing by a mount initially positioned to hold an edge part of the fabric defining the mouth adjacent the housing, the mount being capable of movement to move to a position in which the edge of the fabric defining the mouth is spaced from the housing to define a vent between the edge of the mouth and the housing.
Preferably the mount comprises a rigid element, the element having two spaced-apart substantially linear arms, one arm of the element being received within a retainer slot formed in the housing so as to be pivotal about its axis, the other edge of the loop being connected to the edge of the fabric.
Advantageously a release mechanism is provided adapted initially to retain the mount in a first predetermined position, and to release the mount to permit the mount to move.
The release mechanism may be a frangible device which breaks when a predetermined pressure is present within the air-bag.
The release device may also be device which releases the mount in response to a predetermined signal from a sensor.
Advantageously the air-bag takes the form of a passenger air-bag for a front-seat passenger of a motor vehicle.
In order that the invention may be more readily understood, and so that further features thereof may be appreciated, the invention will now be described, by way of example, with reference to the accompanying drawings in which:
Whilst the invention is being described specifically with reference to a passenger air-bag intended for use by a front-seat passenger, the invention might find applications in other air-bags for use in other situations.